L17 Cellular Models of Diabetes

Question 1

What is the key organ involved in diabetes?

Answer 1

Pancreas

Question 2

What pancreatic cells have been cultured for studying diabetes?

Answer 2

beta cells

Question 3

What three other tissues/cells are responsible for glucose homeostasis?

Answer 3

Adipose and skeletal muscle, as well as neuronal.

Question 4

What stages occur after glucose is obtained during digestion?

Answer 4

Glucose is taken up by cells, and is used either as energy or stored as glycogen.

Question 5

How is glucose homeostasis regulated?

Answer 5

If too high, insulin is released by beta cells of pancreas. This binds to receptors on the body’s cells and glucose is taken up, out of blood.

If too low, glucagon is released from alpha cells of pancreas, causes release of glucose from organ stores (in the liver)

Question 6

What is type I diabetes?

Answer 6

Insulin-dependent diabetes.

Occurs when the body produces no insulin. Often early in life. Commonly autoimmune disease with beta-cells destroyed and targeted.

Can be fixed by taking regular insulin injections for life.

Question 7

What is type II diabetes?

Answer 7

Insulin-independent diabetes.

Occurs when not enough insulin is produced by the body, or when the body does not react to insulin (resistance).

Most common, and occurs as a result of an obese, sedentary lifestyle.

Question 8

What are the cell culture models of diabetes?

Answer 8

Pancreatic beta cells (viral or radiation induction)

Hepatocytes (cancer cell-line)

Skeletal muscle

Adipocytes

Question 9

What animal models of diabetes exist?

Answer 9

Normal rodent.

High fat-fed rodent (T2D - obese)

Pancreas removed surgically/chemically.

NOD mice - T1D

Question 10

What two approaches can be taken to identify location of POI in cell?

Answer 10

Make antibodies - immunpfluorescence

express protein in cell with GFP

Question 11

What three methods can be used to study function of POI in cell?

Answer 11

Knockdown - RNAi, or CRISPR/Cas9.

Overexpress.

Mutant version expression

Question 12

How can genes be introduced into a cell? (transfection)

Answer 12

Virally, using recombinant viruses, retro/adeno-viruses.

Carrier-mediated introduction of DNA - positively charged carrier molecule mixed with DNA.
Carrier-DNA complex binds to plasma membrane and are taken up.

Question 13

What two diabetes related processes can be modeled?

Answer 13

Insulin secretion

Insulin resistance

Question 14

What three channels feed into insulin secretion?

Answer 14

GLUT2

K_ATP channel

Ca²⁺_V channel

Question 15

What two channels are involved in insulin resistance?

Answer 15

Insulin receptors, and GLUT4

Question 16

What principle does the glucose uptake assay work on?

Answer 16

2D-glucose is given to a cell. It’s unable to be metabolised so accumulates in the cell if glucose is able to be transported. Measurements of its amount inside the cell.

Question 17

What are the applications of the glucose uptake assay?

Answer 17

Screening of anti-diabetic ddrugs.

Research on drug metabolism, and insulin signalling pathways.

Question 18

What are the issues with diabetes?

Answer 18

Diagnoses reduces life expectancy. T1=20 years. T2=10 years.

Gyperglycaemia has long term danaging effects.

• Heart disease and stroke
• Nerve damage
• Retionpathy
• Kidney disease